Dust-guard.



ings usually present between the guard and the front wall 3 of the box at the top and bottom I placewithin openings'13 in the guard two or more metallic casings 14 and within the casings a shank and projecting head 15 and a spring 16 on the shank to force the head outwardly, the shank at the end 17 heilig upset'so the shank and head cannot be forced entirely out ot' the casing by the spring. When the guard is inserted in the chamber the heads bear against the surface of the rear wall and thesprings force the opposite surface of the guard against the surface of the wall 3 and prevent the passage ot' dust and dirt to the interior of the box, as shown in F ig. 1.

The guard as thus constructed fulfils the desired requirements of relatively chea first cost, eliiciency in operation and durability. The best embodiment of the invention includes three layers or sheets of wood secured together by' adhesive material and firmly united by rivets.

I have found by extended experiments that the three-ply or sheet guard is the most practical and that guards of more than three sheetsincrea'se the first cost and are not more durable than the three-ply in service. Therefore, in A,practice the guard is preferably comprised of three sheets with the grain of one sheet of the wood angularly disposed to th'e" grain of the other sheets and all united by adhesive material and securely riveted together, and b the term riveted I include the use o nails with heads with the ends upset or bent over or similar devices for performing the requisite function.

'What I claim is:

1. A dust guard comprised of three sheets or layers 0f wood arranged with the grain of one at an angle to the grain of another, adhesive material between the sheets, and rivets passed through the sheets t0 form a. single composite structure, said guard having a circular opening therethrough for the passage'of a journa forth.

2. A dust guard provided with a plurality i of openings, casings within the openings,

shanks with projecting heads within the casings, a'spring on each shank, and means for limiting the outward movements of the heads from the casings, the said springs pressing the heads outwardly when the guard is within the box chamber and forcing the guard against the surface of' the front wall which bounds the said chamber.

In testimony whereof I aix my signature.

LACEY Y. WILLIAMS.

in substance as setA 

